By Mark L. Chambers

After one computer is running a computer-to-computer network or you’ve set up and configured an AirPort/AirPort Express/AirPort Extreme Base Station or Time Capsule, you’re ready to invite other computers with wireless hardware to the party.

How to join in an existing Wi-Fi network

After you have a network set up on one of your wireless-enabled computers, you just need to have the other wireless-enabled computers join that network. You can use the same process to join any wireless network:

  1. Click the Wi-Fi status icon on the menu bar.

    A list of existing network connections appears in the Wi-Fi menu.

  2. Select an existing network connection that you’d like to join.

    If you want to join a network whose name doesn’t appear in the list — also called a closed network, follow these steps:

    1. Select Join Other Network from the Wi-Fi status menu.

    2. Enter the name of the network that you want to join.

    3. If the network uses security encryption, click the Security pop-up menu and choose the proper encryption format — the administrator of the network should be able to tell you the correct format — and then type the password. If you plan on using the network in the future, make sure that the Remember This Network check box is enabled.

    4. Click Join.

    A closed network is another added measure of security — one that’s good enough for most people because it’s very unlikely that a hacker is going to try to hack a hidden network.

How to disconnect from a Wi-Fi network

To disconnect from a Wi-Fi network, you can turn off your Wi-Fi hardware altogether. (Simplicity, they say, is an art.) Another way is to simply connect to another Wi-Fi network — but this option is really only useful if you actually want to connect to another network.

How to turn your Wi-Fi hardware on or off

Being able to turn your Wi-Fi hardware on and off actually has its uses:

  • You might want to use your MacBook in a place where your wireless card shouldn’t be used, like

    • An airplane (when they tell you to turn off all cell phones)

    • A hospital area that doesn’t allow cell phones or other wireless devices

  • Turning off your Wi-Fi hardware conserves your MacBook’s battery life.

To turn your Wi-Fi equipment on or off via the Wi-Fi status icon on the menu bar, give it a click and choose Turn Wi-Fi On/Off from the resulting menu.